Construction anchors and bolts are typically adhesively bonded within apertures formed in masonry, concrete and similar structures. Such anchors and bolts are frequently made of metal and are substantially cylindrical in shape, the anchors including a longitudinally threaded bore and the bolts being threaded about their peripheries. After being secured to the surface, other objects can be readily secured to or suspended from the anchors or bolts.
An example of an adhesively secured construction anchor is illustrated in U.S. Pat. No. 5,263,804 which is assigned to the present assignee. To install that anchor, an aperture is drilled into the masonry surface and then cleaned of debris. A construction adhesive, such as epoxy, is then injected into the aperture from an injection gun. The anchor is inserted within the aperture with a cap positioning the anchor at a desired depth while the adhesive sets to secure the anchor thereto.
An important criteria in securing such anchors is providing the proper size aperture and corresponding amount of adhesive within the aperture for the particular size anchor being utilized. If the amount of adhesive is too little, the anchor may not be properly secured to the structure or air pockets may develop within the mixture.
If too much adhesive is utilized, adhesive may squeeze out of the aperture upon insertion of the anchor which is undesirable. In use, to ensure enough adhesive is applied, the aperture is frequently completely filled with adhesive. Upon insertion of the anchor, approximately 80% of the adhesive is squeezed out and wasted.
Adhesive squeeze out is particularly a problem when the anchor is being secured to a ceiling of a structure since the adhesive may fall onto and injure a user. Additionally, when secured to a ceiling, the adhesive may fall out before the anchor is set therein and/or extrude out due to hydraulic pressures created by air pockets.
As FIG. 6 illustrates, existing fasteners have attempted to solve such problems by employing a separate, tubular metal screen 100 for use with an anchor 102. At the point of installation of such a fastener, the metal screen 100 is inserted over the interior end of the anchor 102 to a random position and is loosely retained on the anchor 102 by friction. The tubular metal screen 100 is then filled with adhesive which is sufficiently viscous to prevent adhesive from seeping through the mesh of the screen.
The metal screen 100 and anchor 102 are then inserted within the aperture, screen first. Upon contacting the bottom of the aperture, the metal screen 100 is forced along the length of the anchor 102 to the position illustrated in FIG. 6. At the same time, the adhesive is expelled from the metal screen 100 and flows about the metal screen 100 and the anchor 102 to secure both the metal screen 100 and anchor 102 within the aperture upon setting.
Such a metal screen 100, however, does not enable proper bonding of the anchor 102 directly to the structure. Accordingly, the pull out strength of the anchor 102 is reduced. Additionally, since the metal screen 100 is loosely and movably placed on the anchor 102 at the point of application, the proper amount of adhesive may not be employed. Furthermore, the metal screen 100 may interfere with the adhesive's bond with the wall of the aperture.
It therefore would be desirable to provide a construction fastener having an adhesive retaining member secured thereto which enables a measured amount of adhesive to be applied within a prescribed aperture of a structure which releases the adhesive upon insertion of the retaining member and fastener within the aperture and does not interfere with the bonding power of the adhesive.